USMLE Prep - Medical Reference Library

Intussusception (Pediatrics) — Ultrasound Diagnosis and Pneumatic Enema Reduction

System: Pediatrics • Reviewed: Sep 1, 2025 • Step 1Step 2Step 3

Synopsis:

Episodic colicky pain, vomiting, and currant‑jelly stools in infants/toddlers. Diagnose with ultrasound (target/doughnut sign) and reduce with air enema under fluoroscopy/US when no perforation; operate if peritonitis, perforation, or failed enema.

Key Points

  • Use the highest‑yield diagnostic test early; do not let testing delay time‑critical therapy.
  • Set objective targets (hemodynamic, neurologic, respiratory) and reassess frequently.
  • Plan definitive source control or disease‑specific therapy when indicated; document follow‑up and patient education.

Algorithm

  1. Suspect clinically; obtain ultrasound to confirm.
  2. If no perforation/peritonitis → pneumatic enema reduction with surgery backup.
  3. If enema fails or perforation present → operative reduction.
  4. Observe post‑reduction for recurrence; evaluate for lead points in older children.

Clinical Synopsis & Reasoning

Episodic colicky pain, vomiting, and currant‑jelly stools in infants/toddlers. Diagnose with ultrasound (target/doughnut sign) and reduce with air enema under fluoroscopy/US when no perforation; operate if peritonitis, perforation, or failed enema.


Treatment Strategy & Disposition

Stabilize ABCs. Initiate guideline‑concordant first‑line therapy with precise dosing and continuous monitoring. Escalate to advanced/procedural interventions based on explicit failure criteria. Define ICU, step‑down, and ward disposition triggers; involve specialty teams early.


Epidemiology / Risk Factors

  • Risk varies by comorbidity and precipitants; see citations for condition‑specific data.

Investigations

TestRole / RationaleTypical FindingsNotes
UltrasoundDiagnosisTarget sign/pseudokidneyHigh sensitivity/specificity
Abdominal radiograph (limited)AdjunctBowel obstruction signsRule out perforation before enema
CBC/electrolytesPre‑procedureAssess dehydration/anemia

Pharmacology

Medication/InterventionMechanismOnsetRole in TherapyLimitations
Pneumatic (air) enema reductionMechanicalImmediateFirst‑line treatmentPerforation risk small
IV fluids/analgesia/antiemeticsSupportiveImmediateStabilize prior to reduction
Antibiotics (selected)AdjunctHoursIf perforation/peritonitis suspected

Prognosis / Complications

  • Outcome depends on timeliness of diagnosis and definitive therapy; monitor for complications.

Patient Education / Counseling

  • Provide red‑flag education, adherence guidance, and explicit return precautions; arrange timely specialty follow‑up.

References

  1. NASPGHAN guidelines and pediatric radiology standards for intussusception — Link